There are a number of tape drive mechanisms in practice and designs for threading tape from a single reel cartridge onto a take-up reel. These various mechanisms deploy a variety of methods for grasping the leader pin from the cartridge. In practice, the leader pin grabbing device must capture and release the leader pin at the proper times and fit into the take-up reel in a manner that maintains the cylindrical nature of the take-up reel.
Once the leader pin is grabbed at the cartridge, the tape attached to the leader pin is threaded by moving the grabbing device with the leader pin to the take-up reel. Some designs employ a leader attached to the take-up reel, while other designs employ an external mechanism to move the grabbing device.
The leader pin grabbing device has the task of capturing and releasing the leader pin from the single reel cartridge. The device must be able to hold the leader pin when the tape tension is both high and low. It is desirable, from a number of manufacturing perspectives, to provide a device that utilizes a minimum amount of external actuators, such as motors, solenoids, etc.